Finding the Fourth Proportional to 2,386.14, 3,578.31 and 998.78

Step by Step Solution

1. Step 1: Write the proportion equation
   2,386.14 : 3,578.31 = 998.78 : x
2. Step 2: Convert to fraction form
   2,386.14/3,578.31 = 998.78/x
3. Step 3: Cross multiply
   2,386.14x = 3,578.31 × 998.78
4. Step 4: Simplify right side
   2,386.14x = 3,573,926.57
5. Step 5: Solve for x
   x = 3,573,926.57/2,386.14
6. Step 6: Final answer
   x = 1,497.79